ALLOCATION OF PRIZES IN CONTESTS WITH PARTICIPATION CONSTRAINTS

We study all-pay contests with an exogenous minimal effort constraint where a player can participate in a contest only if his effort (output) is equal to or higher than the minimal effort constraint. Contestants are privately informed about a parameter (ability) that affects their cost of effort. The designer decides about the size and the number of prizes. We analyze the optimal prize allocation for the contest designer who wishes to maximize either the total effort or the highest effort. It is shown that if the minimal effort constraint is relatively high, the winner-take-all contest in which the contestant with the highest effort wins the entire prize sum does not maximize the expected total effort nor the expected highest effort. In that case, the random contest in which the entire prize sum is equally allocated to all the participants yields a higher expected total effort as well as a higher expected highest effort than the winner-take-all contest.Winner-take-all contests, all-pay auctions, participation constraints.

Projection of two biphoton qutrits onto a maximally entangled state

Bell state measurements, in which two quantum bits are projected onto a maximally entangled state, are an essential component of quantum information science. We propose and experimentally demonstrate the projection of two quantum systems with three states (qutrits) onto a generalized maximally entangled state. Each qutrit is represented by the polarization of a pair of indistinguishable photons - a biphoton. The projection is a joint measurement on both biphotons using standard linear optics elements. This demonstration enables the realization of quantum information protocols with qutrits, such as teleportation and entanglement swapping.Comment: 4 pages, 3 figures, published versio

Engineering vibrationally-assisted energy transfer in a trapped-ion quantum simulator

Many important chemical and biochemical processes in the condensed phase are notoriously difficult to simulate numerically. Often this difficulty arises from the complexity of simulating dynamics resulting from coupling to structured, mesoscopic baths, for which no separation of time scales exists and statistical treatments fail. A prime example of such a process is vibrationally assisted charge or energy transfer. A quantum simulator, capable of implementing a realistic model of the system of interest, could provide insight into these processes in regimes where numerical treatments fail. We take a first step towards modeling such transfer processes using an ion trap quantum simulator. By implementing a minimal model, we observe vibrationally assisted energy transport between the electronic states of a donor and an acceptor ion augmented by coupling the donor ion to its vibration. We tune our simulator into several parameter regimes and, in particular, investigate the transfer dynamics in the nonperturbative regime often found in biochemical situations

Quantum Sensing of Intermittent Stochastic Signals

Realistic quantum sensors face a trade-off between the number of sensors measured in parallel and the control and readout fidelity ($F$) across the ensemble. We investigate how the number of sensors and fidelity affect sensitivity to continuous and intermittent signals. For continuous signals, we find that increasing the number of sensors by $1/F^2$ for $F<1$ always recovers the sensitivity achieved when $F=1$. However, when the signal is intermittent, more sensors are needed to recover the sensitivity achievable with one perfect quantum sensor. We also demonstrate the importance of near-unity control fidelity and readout at the quantum projection noise limit by estimating the frequency components of a stochastic, intermittent signal with a single trapped ion sensor. Quantum sensing has historically focused on large ensembles of sensors operated far from the standard quantum limit. The results presented in this manuscript show that this is insufficient for quantum sensing of intermittent signals and re-emphasizes the importance of the unique scaling of quantum projection noise near an eigenstate.Comment: 5 pages, 4 figure

The biaxial nonlinear crystal BiB3O6 as a polarization entangled photon source using non-collinear type-II parametric down-conversion

We describe the full characterization of the biaxial nonlinear crystal BiB3O6 (BiBO) as a polarization entangled photon source using non-collinear type-II parametric down-conversion. We consider the relevant parameters for crystal design, such as cutting angles, polarization of the photons, effective nonlinearity, spatial and temporal walk-offs, crystal thickness and the effect of the pump laser bandwidth. Experimental results showing entanglement generation with high rates and a comparison to the well investigated beta-BaB2O4 (BBO) crystal are presented as well. Changing the down-conversion crystal of a polarization entangled photon source from BBO to BiBO enhances the generation rate as if the pump power was increased by more than three times. Such an improvement is currently required for the generation of multiphoton entangled states.Comment: 15 pages, 13 figures, published versio

Phosphorylation of 14-3-3ζ at serine 58 and neurodegeneration following kainic acid-induced excitotoxicity

Oxidative stress-induced cell death leads to phosphorylation of 14-3-3ζ at serine 58. 14-3-3ζ is detected at significant levels in cerebrospinal fluid after kainic acid (KA)-induced seizures. Here we examined temporal changes in 14-3-3ζ phosphorylation in the hippocampus and amygdala of mice after KA treatment. Mice were killed at 2, 6, 24, or 48 h after KA (30 mg/kg) injection. We observed an increase in TUNEL and Fluoro-Jade B (FJB)-stained neurons in the hippocampus and amygdala of KA-treated mice. Phospho (p)-14-3-3ζ and p-JNK expression was increased in the hippocampus 2 and 6 h after KA treatment, respectively. In immunohistochemical analysis, p-14-3-3ζ-positive cells were present in the CA3 region of the hippocampus and the central nucleus of amygdala (CeA) of KA-treated mice. Thus, phosphorylation of 14-3-3ζ at serine 58 may play an important role in KA-induced hippocampal and amygdaloid neuronal damage